skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Color transparency in incoherent electroproduction of {rho} mesons off nuclei

Abstract

Color transparency (CT) phenomena in elastic electroproduction of vector mesons off nuclei are usually infected by the onset of coherence length (CL) effects. However, at low energies corresponding to the CLAS experiment at Jefferson Lab (JLab), one can study practically the net CT effects, since CL is much shorter than the nuclear radius. We investigate various manifestations of CT effects using rigorous quantum mechanical approach based on the path integral technique. We include also the effects of {rho} meson decay inside the nucleus leading to a rise of the nuclear suppression towards small values of Q{sup 2}. Motivated by the last CLAS data we predict the A, Q{sup 2} and l{sub c} dependence of nuclear transparency for {rho}{sup 0} mesons produced incoherently off nuclei. We also perform predictions for expected signal of CT corresponding to the planned JLab upgrade to 12 GeV electron beam.

Authors:
 [1]; ;  [2]
  1. Institute of Experimental Physics SAS, Watsonova 47, 04001 Kosice, Slovakia and Czech Technical University, FNSPE, Brehova 7, 11519 Praque (Czech Republic)
  2. Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile)
Publication Date:
OSTI Identifier:
22116933
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1523; Journal Issue: 1; Conference: DIFFRACTION 2012: International workshop on diffraction in high energy physics, Lanzarote, Canary Islands (Spain), 10-15 Sep 2012; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CEBAF ACCELERATOR; COHERENCE LENGTH; COLOR MODEL; ELECTRON BEAMS; ELECTRON REACTIONS; ELECTRONS; ELECTROPRODUCTION; FOUR MOMENTUM TRANSFER; GEV RANGE; NUCLEAR MATTER; NUCLEI; PARTICLE DECAY; PATH INTEGRALS; QUANTUM MECHANICS; RHO-770 MESONS

Citation Formats

Nemchik, J., Kopeliovich, B. Z., and Potashnikova, I. K.. Color transparency in incoherent electroproduction of {rho} mesons off nuclei. United States: N. p., 2013. Web. doi:10.1063/1.4802118.
Nemchik, J., Kopeliovich, B. Z., & Potashnikova, I. K.. Color transparency in incoherent electroproduction of {rho} mesons off nuclei. United States. doi:10.1063/1.4802118.
Nemchik, J., Kopeliovich, B. Z., and Potashnikova, I. K.. Mon . "Color transparency in incoherent electroproduction of {rho} mesons off nuclei". United States. doi:10.1063/1.4802118.
@article{osti_22116933,
title = {Color transparency in incoherent electroproduction of {rho} mesons off nuclei},
author = {Nemchik, J. and Kopeliovich, B. Z. and Potashnikova, I. K.},
abstractNote = {Color transparency (CT) phenomena in elastic electroproduction of vector mesons off nuclei are usually infected by the onset of coherence length (CL) effects. However, at low energies corresponding to the CLAS experiment at Jefferson Lab (JLab), one can study practically the net CT effects, since CL is much shorter than the nuclear radius. We investigate various manifestations of CT effects using rigorous quantum mechanical approach based on the path integral technique. We include also the effects of {rho} meson decay inside the nucleus leading to a rise of the nuclear suppression towards small values of Q{sup 2}. Motivated by the last CLAS data we predict the A, Q{sup 2} and l{sub c} dependence of nuclear transparency for {rho}{sup 0} mesons produced incoherently off nuclei. We also perform predictions for expected signal of CT corresponding to the planned JLab upgrade to 12 GeV electron beam.},
doi = {10.1063/1.4802118},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1523,
place = {United States},
year = {Mon Apr 15 00:00:00 EDT 2013},
month = {Mon Apr 15 00:00:00 EDT 2013}
}
  • We have measured the nuclear transparency of the incoherent diffractive A(e,e'ρ 0) process in 12C and 56Fe targets relative to 2H using a 5 GeV electron beam. The nuclear transparency, the ratio of the produced {rho}{sup 0}'s on a nucleus relative to deuterium, which is sensitive to ρA interaction, was studied as function of the coherence length (I c), a lifetime of the hadronic fluctuation of the virtual photon, and the four-momentum transfer squared (Q 2). Thus, while the transparency for both 12C and 56Fe showed no I c dependence, a significant Q 2 dependence was measured, which is consistentmore » with calculations that included the color transparency effects.« less
  • We study the electroproduction of {rho} mesons in nuclei at intermediate energies, deriving a treatment of the energy lost by the {rho} in each step of multiple scattering. This enables a close match between calculations and the experimental kinematic conditions. A standard Glauber calculation is presented, and then the effects of color-transparency are included. The influence of poor experimental resolution on the extracted transparency is assessed. The effects of {rho} meson decay inside the nucleus are examined, and are typically about 5% at most. This effect disappears rapidly as Q{sup 2} increases from about 1 to 3 GeV{sup 2}, causingmore » a rise in the transparency that is not attributable to color transparency. The size of color transparency effects for C and Fe nuclei is studied for values of Q{sup 2} up to 10 GeV{sup 2}. The detailed results depend strongly on the assumed value of the {rho}N cross section. The overall effects of color transparency are greater than about 10% for both nuclear targets if Q{sup 2} is greater than about 5 GeV{sup 2}.« less
  • Measurements of exclusive incoherent electroproduction of {rho}{sup 0} (770) meson from {sup 2}D, {sup 12}C, and {sup 63}Cu targets up to Q{sup 2} = 4 GeV{sup 2} are proposed using the CLAS detector. The objective of these measurements is to determine the Q{sup 2} dependence of the nuclear transparency ratio for the two nuclear targets: {sup 12}C and {sup 63}Cu at fixed coherence length of quark-antiquark fluctuations of the virtual photon. A sizeable rise of the nuclear transparency is predicted and can be measured in this experiment. A relatively large increase of the nuclear transparency can be considered as amore » signature of the onset of color transparency.« less
  • Ongoing experiments at JLAB investigate the nuclear transparency in exclusive {rho}{sup 0}(770) electroproduction off nuclei. In this work we present transport model predictions for the attenuation of {rho}{sup 0}s in nuclei and for color transparency (CT) effects as observable at CLAS with a 5 GeV electron beam energy. A full event simulation developed here permits to study the impact of actual experimental acceptance conditions and kinematical cuts. The exclusive (e,e{sup '{rho}0}) cross section off nucleons is described by diffractive and color string breaking mechanisms extended toward the onset of the deep inelastic regime. Different hadronization and CT scenarios are compared.more » We show that a detailed analysis of the elementary cross section, nuclear effects, and experimental cuts is needed to reveal the early onset of {rho}-CT at present JLAB energies.« less